1. Field of the Invention
The invention relates to a method for aligning fish with relation to the position of the edges of their gill covers or their shoulder girdle arcs facing the rump by displacing the fish and holding the same in the aligned position, and to a device for carrying out this method comprising a conveyor moving the fish transversely to their longitudinal axis and equipped with conveying chambers defining a support surface for the fish and being separated from each other by means of lateral limiting elements extending transverse to the conveying direction, and a displacement device for displacing the fish within the conveying chambers, the displacement device comprising a displacing element entering between the lateral limiting elements of and in time with the conveying chambers guided past the displacement device and a braking element which comes into contact with the flank of each fish and is operationally related to the displacing element.
2. Description of Prior Art
In commercial fishing set or stationary nets and drift nets are being more and more frequently used in view of increasing prices, especially in the area of energy supply. Besides the improvement in the economy of these catching methods another advantage thus comes into effect which lies in that these nets effect a better selection of size in contrast to trawl or draw nets. This effect is due to the fact that in a set net or a drift net only such fish are retained which are caught with their gill covers in the meshes of the same due to their size, while smaller fish can swim through without hinderance. In contrast, thereto it is unavoidable with a trawl net that the exit for smaller fish is closed with increasing filling of the net, since the bodies of the fish already caught lie transversely obstructing the meshes.
In contrast to the represented advantages of set and drift nets which thus prove to be helpful in endeavours to ensure the continued existence of the fish species forming the basis of human nutrition with fish protein there is the fact that a relatively large number of fish thus caught are damaged at their heads. The reason for this is that the fish, after such nets have been hauled in, must be picked or shaken out of the meshes, the result of which is that the gills and sometimes also the lower jaws are ripped off. Fish so damaged cannot be processed mechanically in a conventional way since usually the measuring and adjusting means of these processing machines start in the area of the head in order to adjust the position of each fish optimally, e.g. for the beheading.
Such means can be taken e.g. from German Pat. No. 26 19 217. This device shows a trough conveyor conveying the fish to be processed transverse to their longitudinal axis. An aligning plate is arranged beside the trough conveyor and running with the same and is equipped with head pressers which engage at the head end of the fish and yield resiliently. The speeds are so coordinated that the head pressers accompany the fish passing by and effect a displacement of the same. A brake shoe which can be lowered onto each fish via operational relationship with the aligning plate according to the timing of the troughs is moved in such a way that the displacement movement of a large fish is stopped earlier and that of a small fish, later. The coordination in this is such that each fish, independent of its size, takes a position which enables an economical beheading cut.
Further a device can be taken from DE-OS No. 31 11 567 in which fish conveyed placed on their belly in troughs of an intermittently driven trough conveyor are adjusted into an optimal beheading position independent of their size. The device consists of a feeler which can be lowered onto the back of the fish during the stationary period of the trough conveyor, which feeler is in operational relationship with a pushing element engaging the head end of the fish. Therein the operational relationship is such that the positioning by displacement is ended when the feeler comes into contact with the back of the fish.
The exact positioning of fish damaged at their heads is not possible with the prior art devices. Since the damages described at the beginning have a certain uniformity it is possible to coordinate the known device accordingly. It is not, however, possible to account for the fact that damaged as well as undamaged fish reach processing randomly.